|VIBRATION OF THIN CIRCULAR RINGS. PART I. SOLUTIONS FOR MODAL CHARACTERISTICS AND FORCED EXCITATION - Lang, T. E|
Modal characteristics and forced vibration of thin circular rings
Keywords: DEFORMATION; EXCITATION; FORCED VIBRATION; RINGS; VIBRATION; DEFORMATION; FORCED VIBRATION; RING
|Control effects on the elastic blade of a helicopter rotor (efectul comenzii la palele elastic ale rotorului de elicopter) - Marinescu, AL|
Forced vibration of blade of helicopter rotor where perturbation forces are due to effect of control
Keywords: BLADES; FORCED VIBRATION; PERTURBATION; ROTARY WINGS; BLADE; FORCED VIBRATION; HELICOPTER ROTOR; PERTURBATION
|Liquid sloshing in spherical tanks - Abramson, H. N.|
Forced vibration characteristics of partially filled spherical tanks - liquid sloshing
Keywords: FORCED VIBRATION; LIQUID SLOSHING; SPHERICAL TANKS; FORCED VIBRATION; LIQUID SLOSHING; SPHERICAL TANK
|Controlability of higher order linear systems - Fattorini, H. O|
Theory and equations on complete controllability of higher order linear systems
Keywords: FORCED VIBRATION; NONLINEAR SYSTEMS; OSCILLATIONS; PARAMETERIZATION; APPROXIMATION; DIFFERENTIAL EQUATIONS; DYNAMIC STABILITY; RESONANT VIBRATION
|A code to unfold scintillation spectrometer polyenergetic gamma photon experimental distributions - Born, U.|
FORTRAN code to unfold sodium iodide scintillation spectrometer polyenergetic gamma photon experimental distributions
Keywords: CYLINDRICAL BODIES; SHOCK WAVES; SPHERICAL WAVES; BLUNT BODIES; FORCED VIBRATION; SHOCK TUBES
|Algebraic surface design and finite element meshes - Bajaj, Chandrajit L|
Some of the techniques are summarized which are used in constructing C sup 0 and C sup 1 continuous meshes of low degree, implicitly defined, algebraic surface patches in three dimensional space. These meshes of low degree algebraic surface patches are used to construct accurate computer models of physical objects. These meshes are also used in the finite element simulation of physical phenomena (e.g., heat dissipation, stress/strain distributions, fluid flow characteristics) required in the com...
Keywords: DYNAMIC STRUCTURAL ANALYSIS; FORCED VIBRATION; FREE VIBRATION; STIFFNESS MATRIX; DISPLACEMENT; FINITE ELEMENT METHOD; THEOREMS
|Forced discontinuous oscillations of a fluid in a pipeline - Natanzon, M. S|
Asymptotic solutions for problem of forced discontinuous cavitational fluid oscillations in pipeline
Keywords: ASYMPTOTES; FORCED OSCILLATION; PIPEFLOW; ASYMPTOTIC SERIES; CAVITATION FLOW; FLUID MECHANICS; FORCED VIBRATION; PIPE FLOW; PIPELINES; CAVITATION FLOW; FLUID MECHANICS
|Mariner Venus 67 structural developmental and qualification vibration test report - Freeland, R. E|
Mariner 5 forced vibration test program
Keywords: MARINER SPACE PROBES; MARINER 5 SPACE PROBE; STRUCTURAL VIBRATION; VIBRATION TESTS; DYNAMIC LOADS; DYNAMIC RESPONSE; FORCED VIBRATION
|MHD Instability and Turbulence in the Tachocline - Werne, Josep|
In this quarter we have begun simulations on the Cray T3E at PSC and we are debugging our code on the TSC. The PSC simulations are examining stratified shear turbulence with a flow-aligned magnetic field and passive tracer particles. We have conducted analysis of neutral simulations to establish a firm basis of comparison. Second-order structure functions have been computed, fit, and compared to theoretical expressions relating the dissipation fields and the structure-function-fit parameters...
Keywords: FLIGHT CONTROL; FREQUENCY RESPONSE; UNSTEADY AERODYNAMICS; MATHEMATICAL MODELS; WIND TUNNEL TESTS; EQUATIONS OF MOTION; FORCED VIBRATION; NONLINEARITY
|Ultrasail - Burton, R.|
Ultrasail is a complete sail system for the launch, deployment, stabilization and control of very large solar sails enabling reduced mission times for interplanetary and deep space spacecraft. Ultrasail is an innovative, non-traditional approach to propulsion technology achieved by combining propulsion and control systems developed for formation-flying microsatellites with an innovative solar sail architecture to achieve sq km-class controllable sail areas, sail subsystem area densities of 1 gm ...
Keywords: VIBRATION TESTS; FREQUENCY RESPONSE; ACCELERATION MEASUREMENT; PAYLOADS; SOUNDING ROCKETS; STRUCTURAL VIBRATION; FORCED VIBRATION; NASA PROGRAMS; ACCELERATION (PHYSICS); RANDOM VIBRATION; DEGREES OF FREEDOM; FLIGHT TESTS; SEMIEMPIRICAL EQUATIONS
|Rate constants and temperature dependences for the reactions of hydroxyl radical with several halogenated methanes, ethanes, and propanes by relative rate measurements - Hsu, K.-J.|
Rate constants of 15 OH reactions with halogen-substituted alkanes, C1 to C3, were studied using a relative rate technique in the temperature range 283-403 K. Compounds studied were CHF2Cl (22), CHF2Br (22B), CH3F (41), CH2F2 (32), CHF3 (23), CHClFCCl2F (122a), CHCl2CF3 (123), CHClFCF3 (124), CH3CF3 (143a), CH3CH2F (161), CF3CHFCF3 (227ea), CF3CH2CF3 (236fa), CF3CHFCHF2 (236ea), and CHF2CF2CH2F (245ca)...
Keywords: DYNAMIC STRUCTURAL ANALYSIS; FLAT PLATES; FREE VIBRATION; MODAL RESPONSE; NASTRAN; FLUID-SOLID INTERACTIONS; PROGRAM VERIFICATION (COMPUTERS); FINITE ELEMENT METHOD; STRUCTURAL VIBRATION; ACOUSTIC EXCITATION; CYLINDRICAL SHELLS; FORCED VIBRATION
|Development of a Composite Tailoring Technique for Airplane Wing - Chattopadhyay, Aditi|
Composite wings have become increasingly popular in recent years due to significant potential of weight savings and stiffness tailoring. For aircraft wings made out of composite materials, aeroelastic tailoring presents an opportunity to enhance the aircraft performance by utilizing their unique stiffness and strength properties. Therefore, the goal of the current research are as follows: (1) Development of a new composite beam modeling, technique to represent the principal load-carrying member ...
Keywords: H-INFINITY CONTROL; TRANSFER FUNCTIONS; ROBUSTNESS (MATHEMATICS); COMPUTERIZED SIMULATION; SELF INDUCED VIBRATION; MAGNETIC BEARINGS; ROTATING SHAFTS; CONTROL SYSTEMS DESIGN; CONTROLLERS; VIBRATION EFFECTS; MATHEMATICAL MODELS; FORCED VIBRATION; MATRICES (MATHEMATICS)
|Terminator and nightside ionosphere of Venus - NON|
No Abstract Available
Keywords: ACOUSTIC EXCITATION; MATHEMATICAL MODELS; MECHANICAL IMPEDANCE; SOUND PRESSURE; ACOUSTIC MEASUREMENT; FORCED VIBRATION; IMPEDANCE MEASUREMENT; PAYLOADS; SPACECRAFT COMPONENTS; STRUCTURAL VIBRATION; VIBRATIONAL SPECTRA; ESTIMATING
|Modeling of thermal lensing in side and end-pumped finite solid-state laser rods - Brackett, Vincent G|
An analytical expression for approximating the time-dependent thermal focal length in finite solid state laser rods was derived. The analysis is based on the temperature variation of the material refractive index caused by optical pumping of these rods. Several quantities were found to be relevant to this analysis. These quantities were the specific thermal profiles of the rods, type of optical pumping employed, type of cooling scheme employed (side and end-cooling parameters), and the specific ...
Keywords: DEGREES OF FREEDOM; MODAL RESPONSE; RUN TIME (COMPUTERS); STIFFNESS; VIBRATION MODE; DYNAMIC RESPONSE; DYNAMIC STRUCTURAL ANALYSIS; STRUCTURAL VIBRATION; COMPUTATION; EIGENVECTORS; FLEXIBILITY; FORCED VIBRATION; FREE VIBRATION
|JavaGenes: Evolving Graphs with Crossover - Globus, Al|
Genetic algorithms usually use string or tree representations. We have developed a novel crossover operator for a directed and undirected graph representation, and used this operator to evolve molecules and circuits. Unlike strings or trees, a single point in the representation cannot divide every possible graph into two parts, because graphs may contain cycles. Thus, the crossover operator is non-trivial...
Keywords: AERODYNAMIC CHARACTERISTICS; FREQUENCIES; FORCED VIBRATION; FLIGHT SIMULATION; DYNAMIC RESPONSE; ALGORITHMS; AERODYNAMIC CONFIGURATIONS; F-16 AIRCRAFT; FUZZY SYSTEMS; FLIGHT CHARACTERISTICS; UNSTEADY AERODYNAMICS; MODELS; COMPUTERIZED SIMULATION; YAW; STABILITY; ROLL; OSCILLATIONS
|An extended structure-based model based on a stochastic eddy-axis evolution equation - Kassinos, S. C.|
We have proposed and implemented an extension of the structure-based model for weak deformations. It was shown that the extended model will correctly reduce to the form of standard k-e models for the case of equilibrium under weak mean strain. The realizability of the extended model is guaranteed by the method of its construction. The predictions of the proposed model were very good for rotating homogeneous shear flows and for irrotational axisymmetric contraction, but were seriously deficient i...
Keywords: AEROELASTICITY; FORCED VIBRATION; STABILIZERS (FLUID DYNAMICS); TAIL ASSEMBLIES; BOUNDARY ELEMENT METHOD; DELTA WINGS; FLUTTER; TRANSONIC FLOW; UNSTEADY FLOW; VORTEX BREAKDOWN; COMPUTATIONAL FLUID DYNAMICS; AIRFOILS; FINITE VOLUME METHOD
|Progressive Damage Analyses of Skin/Stringer Debonding - Daville, Carlos G.|
The debonding of skin/stringer constructions is analyzed using a step-by-step simulation of material degradation based on strain softening decohesion elements and a ply degradation procedure. Decohesion elements with mixed-mode capability are placed at the interface between the skin and the flange to simulate the initiation and propagation of the delamination. In addition, the initiation and accumulation of fiber failure and matrix damage is modeled using Hashin-type failure criteria and their c...
Keywords: AERODYNAMIC CHARACTERISTICS; SUBSONIC SPEED; HARMONIC ANALYSIS; DATA PROCESSING; DYNAMIC TESTS; MATHEMATICAL MODELS; WIND TUNNEL TESTS; F-16 AIRCRAFT; FORCED VIBRATION; OUTPUT; RIGID STRUCTURES; NONLINEARITY
|Computational Analysis of a Chevron Nozzle Uniquely Tailored for Propulsion Airframe Aeroacoustics - Massey, Steven J.|
A computational flow field and predicted jet noise source analysis is presented for asymmetrical fan chevrons on a modern separate flow nozzle at take off conditions. The propulsion airframe aeroacoustic asymmetric fan nozzle is designed with an azimuthally varying chevron pattern with longer chevrons close to the pylon. A baseline round nozzle without chevrons and a reference nozzle with azimuthally uniform chevrons are also studied...
Keywords: WIND TUNNEL TESTS; DAMPING; ANGLE OF ATTACK; ROLLING MOMENTS; NONLINEARITY; DYNAMIC STABILITY; TRANSONIC WIND TUNNELS; AERODYNAMIC CONFIGURATIONS; FLIGHT ENVELOPES; FORCED VIBRATION; DATA ACQUISITION; GRAPHICAL USER INTERFACE; WING SPAN
|Radar E-O image fusion - Oneil, William F|
The fusion of radar and electro-optic (E-O) sensor images presents unique challenges. The two sensors measure different properties of the real three-dimensional (3-D) world. Forming the sensor outputs into a common format does not mask these differences. In this paper, the conditions under which fusion of the two sensor signals is possible are explored. The program currently planned to investigate this problem is briefly discussed.
Keywords: ADAPTIVE CONTROL; AIRFRAMES; ELECTRONIC CONTROL; FLIGHT TESTS; LEAST SQUARES METHOD; MAXIMUM LIKELIHOOD ESTIMATES; POSTFLIGHT ANALYSIS; PROPULSION; AIRCRAFT CONTROL; AIRCRAFT PERFORMANCE; F-15 AIRCRAFT; FLIGHT CHARACTERISTICS; FLIGHT CONDITIONS; FORCED VIBRATION; MINIMUM DRAG; OPTIMAL CONTROL
|The velocity and vorticity fields of the turbulent near wake of a circular cylinder - Wallace, James|
The purpose of this research is to provide a detailed experimental database of velocity and vorticity statistics in the very near wake (x/d less than 10) of a circular cylinder at Reynolds number of 3900. This study has determined that estimations of the streamwise velocity component in flow fields with large nonzero cross-stream components are not accurate. Similarly, X-wire measurements of the u and v velocity components in flows containing large w are also subject to the errors due to binorma...
Keywords: AEROACOUSTICS; UNSTEADY AERODYNAMICS; FLUTTER; FORCED VIBRATION; INVISCID FLOW; NOISE GENERATORS; NOISE REDUCTION; TURBULENCE; VIBRATION DAMPING; AEROELASTICITY; COMPUTATIONAL FLUID DYNAMICS; COMPUTER PROGRAMS; HIGH REYNOLDS NUMBER; MATHEMATICAL MODELS; NAVIER-STOKES EQUATION; NONLINEARITY; TURBOMACHINERY
|Liquid Crystal on Silicon Wavefront Corrector - Pouch, John|
A low cost, high resolution, liquid crystal on silicon, spatial light modulator has been developed for the correction of huge aberrations in an optical system where the polarization dependence and the chromatic nature are tolerated. However, the overall system performance suggests that this device is also suitable for real time correction of aberration in human eyes. This device has a resolution of 1024 x 768, and is driven by an XGA display driver...
Keywords: AEROSHELLS; FORCED VIBRATION; DEGREES OF FREEDOM; SIMULATION; DAMPING; DATA REDUCTION; ANGULAR VELOCITY; MACH NUMBER; VIKING MARS PROGRAM; BALLISTIC RANGES; MARS EXPLORATION; MARS ROVING VEHICLES; SPACE CAPSULES; CENTER OF GRAVITY; MARS PATHFINDER; ANGLE OF ATTACK; NOSES (FOREBODIES)
|Systematic errors of a horizon sensor due to the nonsphericity of the planet - Ioffe, I. G|
Systematic errors of horizon sensor due to nonsphericity of planet
Keywords: ELASTIC PROPERTIES; HYDRAULIC EQUIPMENT; MODULUS OF ELASTICITY; NUMERICAL ANALYSIS; OPTIMAL CONTROL; ROTATING SHAFTS; SELF INDUCED VIBRATION; VIBRATORY LOADS; SHAFTS (MACHINE ELEMENTS); TURBINE WHEELS; VIBRATION DAMPING; VIBRATION EFFECTS; DYNAMIC RESPONSE; EQUATIONS; EQUATIONS OF MOTION; FORCED VIBRATION
|Numerical Study of Magnetic Damping During Unidirectional Solidification - Li, Ben Q|
A fully 3-D numerical model is developed to represent magnetic damping of complex fluid flow, heat transfer and electromagnetic field distributions in a melt cavity. The model is developed based on our in-house finite element code for the fluid flow, heat transfer and electromagnetic field calculations. The computer code has been tested against benchmark test problems that are solved by other commercial codes as well as analytical solutions whenever available...
Keywords: AEROELASTICITY; DYNAMICAL SYSTEMS; VISCOELASTICITY; FLUTTER ANALYSIS; FIBER OPTICS; OPTICAL MEASURING INSTRUMENTS; NEURAL NETS; ACCELERATED LIFE TESTS; STATIC DEFORMATION; PROPULSION SYSTEM PERFORMANCE; FORCED VIBRATION; VIBRATION DAMPING; AEROSPACE SYSTEMS; TURBOMACHINERY; ROTOR DYNAMICS; MAGNETIC SUSPENSION; DYNAMIC STRUCTURAL ANALYSIS; GAS TURBINES; MAGNETIC BEARINGS; DYNAMIC RESPONSE
|MIT 2.003J Dynamics and Control I, Fall 2007 - MIT OpenCourseWare|
This class is an introduction to the dynamics and vibrations of lumped-parameter models of mechanical systems. Topics include kinematics; force-momentum formulation for systems of particles and rigid bodies in planar motion; work-energy concepts; virtual displacements and virtual work; Lagrange's equations for systems of particles and rigid bodies in planar motion; linearization of equations of motion; linear stability analysis of mechanical systems; free and forced vibration of linear multi-deg...
Keywords: dynamics and vibrations of lumped-parameter models; mechanical systems; Kinematics; Kane's method; Force-momentum formulation; systems of particles; rigid bodies in planar motion; Work-energy concepts; Virtual displacements; virtual work; Lagrange's equations; Linearization of equations of motion; Linear stability analysis; Free vibration; forced vibration; linear multi-degree of freedom models; matrix eigenvalue problems; numerical methods; MATLAB